There is known a semiconductor chip module called multi-chip module (MCM). In a conventional multi-chip module, multiple silicon chips which have been manufactured by separate processes are horizontally packaged onto a unifying substrate. Bare silicon chips are exposed, and are respectively connected with each other through a wiring formed on a ceramic or a build-up board (See for example Japanese Unexamined Patent Publication No. 6-283661).
However, in order to secure a substantial channel area in response to the wiring specification of the ceramic or the build-up board in JP-A-6-283661, a clearance between adjacent chips has to be large.
Additionally, since the large clearance between the chips elongates a wiring length between the chips, it may be difficult to transmit data at high rates between the chips such as large-scale integration (LSI) chips. Further, when the wiring length is elongated, the driver installed in the LSI has to be changed into another lager driver, and the size of the LSI may be accordingly larger. Furthermore, the provision of a large number of channels in the board is limited by the wiring specification.
On the other hand, recently, there has been developed a board having fine wirings such as a build-up board (See for example Japanese Unexamined Patent Publication No. 2001-94033). However, to manufacture the build-up board, a specific process or an equipment is additionally needed. Thus, its cost may be increased.